Conventionally, a structure which is common to vehicle seats, such as aircraft seats and automobile seats, is stated in Japanese Patent Laid-Open Publication No. 2001-057916. With this structure, to a leg part which is to be fixed to the floor of a vehicle, a base frame is fixed, and thereto a bottom frame and a seat back frame are connected. To the bottom frame configured in this way, a bottom cushion on which a sitting person is to sit is mounted, and to the seat back frame, a seat back cushion which can receive the back of a sitting person is mounted. The seat back cushion is mounted to a back plate member, and the seat back frame is mounted such that it surrounds the side edge part and the upper edge part of the back plate member.
With the aircraft seat, the seat back frame is formed with a tube frame for reinforcing the back plate member. The load of a sitting person is received by this seat back frame through the back plate member.